title: Analysis of the local organization and dynamics of cellular actin networks.
abstract: Actin filaments, with the aid of multiple accessory proteins, self-assemble into a variety of network patterns. We studied the organization and dynamics of the actin network in nonadhesive regions of cells bridging fibronectin-coated adhesive strips. The network was formed by actin nodes associated with and linked by myosin II and containing the formin disheveled-associated activator of morphogenesis 1 (DAAM1) and the cross-linker filamin A (FlnA). After Latrunculin A (LatA) addition, actin nodes appeared to be more prominent and demonstrated drift-diffusion motion. Superresolution microscopy revealed that, in untreated cells, DAAM1 formed patches with a similar spatial arrangement to the actin nodes. Node movement (diffusion coefficient and velocity) in LatA-treated cells was dependent on the level and activity of myosin IIA, DAAM1, and FlnA. Based on our results, we developed a computational model of the dynamic formin-filamin-actin asters that can self-organize into a contractile actomyosin network. We suggest that such networks are critical for connecting distant parts of the cell to maintain the mechanical coherence of the cytoplasm.
authors.affiliation: Mechanobiology Institute, National University of Singapore, Singapore 117411, Republic of Singapore.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Luo
authors.forename: Cheng-han
authors.initials: CH
authors.lastname: Yu
authors.forename: Zi Zhao
authors.initials: ZZ
authors.lastname: Lieu
authors.forename: Jun
authors.initials: J
authors.lastname: Allard
authors.forename: Alex
authors.initials: A
authors.lastname: Mogilner
authors.forename: Michael P
authors.initials: MP
authors.lastname: Sheetz
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Bershadsky
mesh_terms: D008841:Actin Cytoskeleton / Q000502:physiology*; D000205:Actomyosin / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003198:Computer Simulation; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism*; D005326:Fetal Proteins / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D064448:Filamins / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D000080865:Formins; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007124:Immunoenzyme Techniques; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008962:Models, Theoretical; D024462:Myosin Type II / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D005326:Fetal Proteins; D064448:Filamins; C529499:FlnA protein, mouse; D000080865:Formins; C491734:Lat protein, mouse; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D034741:RNA, Small Interfering; D000205:Actomyosin; C500365:Daam1 protein, mouse; D024462:Myosin Type II; D020741:rho GTP-Binding Proteins